Electric-circuit-making device.



R. B. BENJAMIN.

' ELECTRIC CIRCUIT MAKING DEVICE.

APPLICATION FILED APR. I9, 1912.

1 ,246,84=5. Patented Nov. 20, 1917.

2 SHEETSSHEET I- "Mm... 1@ 142g 1. g Z0 J2 25 42a "E I III III B. BfBENJAMlN.

ELECTRIC CIRCUIT MAKING DEViCE.

APPLICATION FILED APR, 19. 1912.

1 ,246,84=5 Patented Nov. 20, 1917.

2 SHEETS-SHEET 2.

UNITED STATES PATENT OFFICE.

REUBEN B. BENJAMIN, OF CHICAGO, ILLINOIS, ASSIGNOR T0 BENJAMIN ELECTRIC MFG. COMPANY, OF CHICAGO, ILLINOIS, A CORPORATION OF ILLINOIS.

ELECTRIC-CIRCUIT-MAKING DEVICE.

Specification of Letters Patent.

Patented Nov. 20, 1917.

Application filed. April 19, 1912. Serial No. 691,968.

To alt whom it may concern:

Be it known that I, REUBEN B. BENJAMIN, a citizen of the United States, residing at Chicago, in the county of Cook and'State of Illinois, have invented new and useful lnuirm'cmeuts in Electric- Circuit-l\laking Devices, of which the following is a full, clear, concise, and exact description, referonce being had to the accompanying drawing, forming a part of this specification.

My invention pertains to electric-circuitmaking devices, particularly attachment plugs; and the invention is especially applicable to attachment plugs of the kind generally known as separable, i. c., plugs consisting of two separable portions, one of which is adapted for connection with a wall socket or the like, and the other of which carries binding terminals for receiving lead wires and has contacts for making electrical connection with the first named portion and the wall socket. It is the principal object of my invention to provide an improved form of separable attachment plug, which will have good contact making qualities, which will be (lurableand convenient in use, which will be of a simple and economical construction and of neat appearance, the binding terminals of which will be eit'cctively relieved from strain, and the separable portions of which will come apart readily in case of an accidental pull being imparted to the lead wires, either in an angular direction or otherwise. It is a further object of my invention to improve upon the construction of attachment plugs generally. And it is a still further object of my invention-to provide an improved form of plunger contact for use in electric-circuit-mak ing devices.

A separable attachment plug constructed the plug being shown united, the section belng taken as on the line l1 of Fig. 3;

Fig. 2 is a sectional plan of the same, the section being. taken on the line 2-2 of Fig. 1;

Fig. 3 is a plan of the insertible portion of the plug, or body, the insulating button which carries the center contact of such body having been removed;

Fig. 4 is a vertical section through the body and a part of the outer portion of the plug, or shell, the section being taken on the line l t of Fig. 3, looking in the direction of the arrows;

Fig. 5 is a view similar to F ig; 4, the section being, however, taken on the line 55 of Fig. 3, looking in the direction of the arrows;

Fig. 6 is a detail View of the removable insulating buttonwhich forms a part of the body, and which carries the center contact of said body;

Fig. 7 is a fragmentary view of the lower part of the shell, showing projections which areprovided to facilitate the disconnection of the body from the shell;

Fig. 8 is a dctail'view of the plunger contact of the shell;

Fig. 9 is a perspective detail view of the binding plate for the center contact of the body of the plug; and

Fig. 10 is a perspective view of a member which forms the side contacts for the body, and at the same time the binding plate for such side contacts. I

Like reference characters refer to like parts throughout the following specification and the several figures of the drawings.

The separable attachment plug which I have chosen as suitably illustrating my invention, and which I have shown in the drawings, is of the ordinary type including two separable portions, which portions will 'I for making electrical connection witl corresponding contacts of the shell.

Referring now particularly to Figs. 1

and 2, the shell comprises a threaded sleevecontact 12 adapted for engagement with the corresponding threaded contact of a wall socket or the like. The lower end of the sleeve-contact is reduced in diameter so as to form a neck 13'and ashoulder 14, which shoulder cooperates with the side contacts of the body, hereinafter to be described, so asto maintain the body in connection with the shell. The metal of the sleeve-contact 12 is pressed up, above the shoulder 14, so as to form a plurality of projections 1 1 (Fig.

7), the tops of which are flush with the neck 13. These projections aid 'in the separating of the body from the shell, as will be hereinafter described. Molded about the lower end of the sleeve-contact 12 so as to surround the neck 13, is a ring 15, formed of hard rubber or the like, which ring is adapted to be grasped by the fingers when it is desired to insert the shell into, or withdraw it from, the wall socket.

The upper end of the sleeve-contact 12 is bent over inwardly so as to form a retaining flange 16. An insulating button 17, preferably formed of hard rubber or the like, is secured to the upper end of the sleeve-contact 12, and carries the center contact of the shell.

In order to secure the button 17 in position, an insulating washer 18 is provided, the button 17 and the washer 18 being placed on opposite sides of the flange 16' of the sleeve-contact, so as to clamp the flange between them. The securing of the button 17 to the washer 18 is effected by means of a tubular member 19, formed of brass or other electrically-conductive material and forming the center contact of the shell. The member 19 is formed with a flange at its upper end, which engages the top side of the button 17; and is flanged outwardly, at 20, at its lower end, beneath the washer 18, thus securing thebutton and the washer together with the flange 16 of the sleeve-contact firmly clamped between them.

The tubular center-contact 19 has mounted therein, a movable plunger which forms the inner center-contact of the shell. To this end, the tubular contact 19 is constricted somewhat, adjacent its center, so as to form a shoulder 21. The plunger 23 consists of a hollow member, open at its upper end, and of such shape as to conform to the inner 1 surface of the tubular contact 19; it is enlar'ged at its upper end so as to form a shoulder 22 which, by engaging against the should'er 21 of the contact 19, prevents the plunger from coming out of place. The plunger 23 is formed with a plurality of longitudinal slots 24, extending from its upper end downward beyond the shoulder 22, which slots render the upper end of the plunger collapsible inwardly and permit it to be pushed upward through the restricted lower end of the contact 19. When the plunger has been thus pushed up through the lower contact 19, thus serving to hold the plunger outward with its shoulder 22 engaging against the shoulder 21 of the contact 19. It will be seen that the construction described above is exceedingly simple and economical, and permits of very easy assembling ofthe parts; moreover, the tendency of the upper end of the plunger 23 to spring outward, results in a good electrical connection between the plunger and the contact 19. As has been said, the outer end of'the contact 19forms the center contact of the shell, and the plunger 23 forms an inner center-contact for the shell. The body is provided with contacts which engage the plunger 23 and the inner surface of the sleeve-contact 12, respectively.

The body comprises a base 26, formed of hard rubber or other moldable insulating material, and shaped so that it may be con- 'veniently handled in inserting the body into,

and withdrawing it from, the shell. The base 26 carries the binding terminals, and a pair of outer contacts for engaging within the sleeve contact 12 of the shell. To the base 26 is'secured a button 42 which carries the'centcr contact of the body, so that said center contact will engage the plunger 23, when the body and the shell are connected together. The button 42 protects, and partly hides, the binding terminals carried by the base 26; and it also serves to grip the lead conductors, and thus relieve the binding terminals from any strains which may be imparted to the lead conductors.

The outer'co'ntacts, for engaging within the sleeve-contact 12 of the shell, are designated 36; and they form parts of a plate 34: (Figs. 1, 3 and 10). The plate 34 is embedded in the material of the'base 26, so as to be somewhat below the upper surface thereof; .and its ends are bent up so as to emerge from the base, one at each side of the center thereof, to form the outer contacts 36. These latter are formed with humps37 convenientlydisposed to engage over the shoulder 14 of the sleeve-contact 12, and arebent inwardly, as at 36, beyond said humps, so as to provide beveled surfaces'for facilitating the insertion of the body into the shell. The base'26 is formed with a depression 33 in its upper surface,

whereby a portion 35 of the embedded plate 34 is exposed, which portion carries a binding screw 38. The exposed portion 35 of the embedded plate 34, and the binding screw 38, together form one of the binding terminals of the body.

A second plate,'39, is embedded in the material of the base 26, on the same plane as the plate 34:; but the plate 39 is so located with respectQtO-the plate 34 asto be effectively insulated?gtherefrom by the interven-.

ing material ofthe base. The base 26 is formed with a' second depression, 32, similar to the depression 33 and disposed oppositely thereto, whereby the end 39 of the plate 39 is exposed. The end 39 carries a binding screw 40, thus forming the other binding terminal of the body. The end of the plate 39 opposite to the end 39, has secured thereto an internally screw-threaded socket 4.1, the upper part of which emerges from the upper surface of the base 26, at the center thereof. This socket receives the lower end of a screw 14 which secures the button 42 in place, and the top end of which forms the center contact of the body, engaging the plunger 23 of the shell when the body is connected with the shell.

The base 26, is formed, at the rear side thereof, with a main passage 27, through which the lead conductors 30 and 31 may be passed. The base is also formed with passages 28 and 29, opening, at their upper ends, adjacent the bindiiig-terminal-containing depressions and 33, respectively, and opening, at their lower ends, into the main passage 27. The lower portions of the outer surfaces of the passages 28 and 29 form shoulders 28 and 29, adapted to clamp the conductors 30 and 31,'respecti\'ely, as will hereinafter be described, it being understood that the conductors 30 and 31 pass through the passages 28 and 29 and are secured beneath the binding screws 40 and 38 respectively (Fig. 4).

The button 42 is of substantially hemispherical shape at its .upper part, being enlarged somewhat at .its lower part so as to fit snugly into the opening of the shell (Fig. 4) and thus insure a close fit between the body and the shell. The height of the button 42 is such that no part of it will strike the inner edge of the shell if the body he moved by tilting it about a point of contact between the base 26, and the insulating ring 15 of the shell. The button is formed with two flat surfaces 42 one at each side, for accommodating the outer :contacts 36; and is hollowed out at the center of its lower side, to form a chamber 43 for receiving the projecting portion of the socket 41. The

screw 44 passes downward through the but-.

ton and enters the socket 41, thus securing the button to the base 26. Extend ng downwind from the button 42, are two laterally ward.

separated projections 45, spaced apart suflicicntly for them to straddle the material of the base 26 which lies between the openings of the passages 28-and 29. The projections 45 enter the upper ends of the passages 28 base 26. The conductors 30' and 31 are then passed through the passage 27, and .the passages 28 and 29 respectively, and secured beneath the binding terminals 40 and 38. hen the conductors have been thus secured, the button 42 is placed in position, with its projections 45 entering the passages 28 and 29 and engaging against the conductors 30 and 31. The screw 44 is then passed through the button into the socket 41 and is tightened up, the conductors being thus clamped as described above. The button 42 protects and partly hides the binding screws 38 and 40, the ends of the conductors being thus contained in chambers which are almost completely closed; so that short circuiting is effectually prevented.

In the use of the separable attachment plug herein described, the shell is first inserted into a Wall socket or the like, so that its sleeve-contact 12 makes connection with the threaded contact of the socket, and its center contact 19 makes connection with the center contact of the socket. When it is desired that current be supplied to the translating device which will be connected between the ends of the lead conductors, the body is simply pushed into the shell. \Vhen this is done, the humps 37 on'the side contacts 36 will snap past the neck 13 and engage behind the shouldcr 14, this action being facilitated by the inwardly bent ends 37 of the contacts 36. which act as cam surfaces, causing the contacts 36 to be sprung in- At the same time the head of the screw 44 will engage the plunger 23 and force the same inward against the action of the spring 25. The humps 37, by their engagement behind the shoulder 14, hold the body in position firmly in the shell, the body being prevented from shaking laterally by reason of the engagement of the enlarged contacts of the shell and those ofthe body.

While the bodv is firmly held in position in merely exercising a direct pull upon the body. However, the body may be withdrawn more easily, and with less jar to the fixture, by slightly turning the body with respect to the shell, at the same time exerting a light pull. The efi'ect of such turning movement will be that the humps 37 of the outer contacts 36 will engage the projection 14- of the shell (Fig. 7), and thereby will be forced toward each other, thus freeing them from engagement behind the shoulder 14. After the body has been turned thus, it may be withdrawn with the utmost ease, the endwise pressure exerted by the springpressed plunger 23 aiding in such withdrawal.

The plug described above is of an elficient and durable construction and may be prodilced at a reasonable cost. It has the advantage that the number of loose contacts and other parts are reduced to a minimum, and that the binding terminals are protected against strains or accidental loosening. The portion of the body which protrudes from the shell is light and neat; and the body is not liable to breakage in case of accidental dropping or the like. As has been pointed out above, the body may ,be inserted into, and withdrawn from, the shell, without any appreciable jar being imparted to the fixture.

I have described and shown one form in which my invention may be embodied; but I wish it to be. understood that the invention may be embodied in other forms, and that changes may be made in the construction which I have described and shown, within the scope of the appended claims.

Having thus described my invention,what I claim as new and desire to secure by Letters Patent, is:

1. In an attachment plug, an insulating base member having a passage therein for the reception of a lead conductor, a second insulating member non-rotatably mounted with respect to said first member having a conductor clamping projection entering said passage and clamping the conductor there- 1n when said members are drawn together, means for drawing said insulating member toward the face of the insulating base, and contact-making parts on said plug.

2. In an attachment plug, an insulating base member having two passages extending therethrough and opening at the front thereof at laterally separated points, said passages being adapted for the reception of lead conductors, a second insulating member, having laterally separated projections adapted to enter said passages when said members are drawn toward each other, means for drawing said members toward each other, whereby lead conductors present in said passages will be clamped therein by said projections, and contact making parts.

3. In an attachment plug, an insulating base member having two passages extending therethrough and opening at the front thereof at laterally separated points, said passages being adapted to receive lead conductors, a second insulating member, hav-' ing laterally-separatet'l projections adapted to enter said passages when said members are drawn toward each other, a screw passing through said members so as to draw the same together when tightened, said screw being disposed so as to form an end con-, tact, and a side contact.

4. In. an attachment plug, the combination with a shell adapted for insertion into a wall socket or the like, and comprising a threaded sleeve-contact and a center contact, of a bodv adapted for insertion into said shell, said body comprising a base member having two passages extending therevthrough and opening at the front thereof at laterally separated points, said passages being adapted to receive lead conductors, a second insulating member, having laterally separated projections adapted to enter said passages when said members are drawn to ward each other, whereby lead conductors present in said passages will be clamped therein by said projections. and contacts carried by said body adaptedto make electrical connection with the contacts of said shell.

5. In an attachment plug, the combina-' tion with a shell= adapted for insertion into a wall socket or the like and comprising a threaded sleevecontact and a center con-- tact, of a body adapted for insertion into said shell, said body comprising a base member, binding terminals mounted on said base member, an insulating member removably secured to said base member and covering and protecting said binding terminals, a center contact carried by said insulating member and electrically connected with one of said binding terminals, and an outer contact carried by said base member and connected with the other binding terminal.

6. In an attachment plug, the combination with a shell adapted for insertion into a wall socket or the like and comprising a threaded sleeve-contact and a center contact, of a body adapted for insertion into said a shell, said body comprising a base member,

binding terminals carried by said base member, an outer contact carried by said base member and electrically connected with one of said binding terminals, "an insulating member covering and protecting said binding terminals, and a screw for securing said insulating member to said base member, said screw being electrically connected with the other binding terminal and forming the center contact of the body.

7. In an attachment plug, the combination with a shell adapted for insertion into. a wall socket or the like, and comprising a threaded sleeve-contact and a center contact, of a body adapted to be inserted into said shell, said body comprising a base formed of moldable insulating material, bindin terminals mounted upon the front side of said base, side contacts molded into said base and connected' with one of said binding terminal s,a socket molded into said base and connected with the other binding terminal, an insulating member adapted to be mounted upon the front side of said base so as to protect said binding terminals, and a screw passing through said insulating member and entering said socket, said screw 7 serving as a center contact for said body.

8. In an attachment plug, the combination with a shell adapted for insertion into a wall socket or the like and comprising a threaded sleeve-contact and a center contact, of a body adapted for insertion into said shell, said body comprising a base member having two passages extending therethrough and opening at the front thereof at laterally separated points, binding terminals carried by said base member to receive lead conductors passed through said passages, an outer contact electrically connected with one of said binding terminals, an insulating member adapted to be secured to said base and having projections adapted to enter said pas sages and clamp the conductors therein, and a center contact carried by said insulating member, and electrically connected with the other binding terminal.

9. In an attachment plug, the combination with a shell adapted for insertion into a Wall socket or the like and comprising a threaded sleeve contact and a center contact, of a body adapted for insertion into'said shell, said body comprising a base member having two passages extending therethrough and opening at the front thereof at laterally separated points, binding terminals carried by said base member adjacent the front ends of said passages to receive lead conductors passed through said passages, an outer contact electrically connected with one of said binding terminals, an insulating member adapted to be secured to said base so as to protect said binding terminals and having projections adapted to enter said passages and clamp the conductors therein, and a cention with a shell for insertion into a wall socket or the like, comprising a threaded sleeve contact and a center contact, of a body for insertion into said shell, comprising a base member formed of moldable insulating material, a plate embedded into said material having upturned ears emerging from said base member and forming outer con tacts for engagement with the sleeve contact of the shell, and a center contact associated with said base engaging with the center contact of said shell.

11. In an attachment plug, the combination With a shell for insertion into a wall socketfor the like, comprising a threaded sleeve contact and a center contact, of a body for insertion into said shell, comprising a base member-formed of moldable insulating material, a plate embedded into said material, a portion of said plate being exposed to receive a binding screw, said plate having upwardly extending ears projecting from the upper surface of the base member and forming outer contacts for engaging the sleeve contact of the shell, and a center con tact associated with said base member for engaging the center contact of the shell.

12. In an attachment plug, the combination with a shell adapted for insertion into a ,wall socket or the like and comprising a threaded sleeve contact and a center contact. of a body adapted for insertion into said shell, said body comprising a base member formed of moldable insulating material, a

plate embedded in the material of said base member and having members projecting upwardly from the ends thereof so as to emerge from the material of said base memher and form outer contacts for engagement with the sleeve contact of said shell, means for connecting a lead conductor with said plate, a second plate embedded in the material of said insulating base, means for connecting alead conductor with said secondnamed plate, an insulating button adapted, when secured to said base member, to clamp the conductors between itself and said base member, and means, passing through said insulating button, and entering said secondnamed plate, for securing said button to said base member, said securing means also serving as a center contact adapted to engage the center contact of said shell. 1.3. In an attachment plug, the combination with a shell adapted for insertion into a wall socket or the like and comprising a threaded sleeve contact and a center contact, of a body adapted for insertion into said shell, said body comprising a, base member formed ofmoldable insulating material, a- Plate embedded in the material of said base member and having a portion thereof exposedto receive a binding screw for the attachment of a lead conductor, said plate being provided at its. ends, with upwardly extending members emerging from the material of said base so as to form outer contacts for engaging the sleeve contact of said shell, a second plate embedded in the material of said base member and having a portion thereof exposed to receive a binding terminal for the attachment of a second lead conductor, an insulating button adapted, when secured to said base-member, to grip the lead conductors secured to said binding terminals between itself and said base member, and means passing through said insulating button and entering said secondnamed plate for securing said insulating button to said base member, said securing means also serving as a center contact aldalpted to engage the center contact of said s e 14. In an attachment plug, the combination with a body including an insulating contact of said body when said body and.

said shell are connectedtogether, and means 7 for causing the outer contact of said body to move inward when said'body is rotated with respect to said shell, whereby the removal of said body from said shell is facilitated.

15. In an attachment plug, the combination with a body comprising an insulating member, an outer contact associated with said insulating member and provided with an outwardly extending projection, a center contact associated with said insulating memher, and binding terminals for said contacts, of a shell comprising .a threaded sleeve contact having an internal peripheral shoulder, adjacent its lower end, above which the projection of said outer contact can engage to maintain said body in connection with said shell, said shell being formed with a plurality of releasing projections above said shoulder, said releasing projections being adapted to engage the projection of said outer contact so as to move the same inward upon said'body being rotated with respect to saidshell, an outer center contact for said shell, and an inner center contact for said shell electrically connected with said outer center contact and adapted for engagement bythe center contact of said body.

16. In an attachment plug the combination with abody comprising an insulating member, an outer contact associated with said insulating member, a center contact associated with said insulating member, and

binding terminals for said contacts, of a tween them, the upper end of said conduct ing member forming an outer center contact for said shell, and an inner center contact connected with the lower end'of said conducting member.

17. In an electric circuit making device,

a plunger contact comprising a tubular con ductin member having the lower portion thereol constricted so as to form a shoulder and a hollow plunger having the upper portion enlarged to form a shoulder for engagement with the shoulder of said tubular member, said hollow plunger being formed with longitudinal slots to permit the enlarged end of the same to be inserted through the reduced end of said tubular member.

18. In an electric circuit making device, the combination with a tubular member having the upper end thereof closed and the lower end thereof constricted so as to form a shoulder, of a hollow plunger having the upper end thereof enlarged so as to form a shoulder for engagement with the shoulder of said tubular member, the enlarged upper portion of said plunger being formed with slots so as to permit the same to be inserted through the reduced lower end of. said tubular member, and a spring disposed between said plunger and the closed end of said tubular member.

19. A separable attachment plug comprising a shell having an inwardly extending annular contact portion at its outer end, an insulating binding terminal carrying memher, and a plurality ofspring contacts carried thereby having free inner ends which snap over said annular contact to hold the binding terminal carryingmember in place.

20. A separable attachment plug comprising an insertible member having an inwardly extending annular contact portion at its outer end, an insulating bindin terminal carrying member, and a plurality of spring contacts carried thereby having free inner ends which snap over said annular cont-act to hold the binding terminal carrying member in place.

21. A separable attachment plug compris ing an insertible member having a contact,

. a binding terminal carrying member carrying a contact for snap engagement with said first contact, and means whereby rota tion of said binding terminal carrying member with respect to said insertible member will cause'said contacts to move to a position in which they can be easily disengaged.

22. A separable attachment plug comprising an insertible member having a contact, a binding terminal carrying member carrying a contact for snap engagement with said first contact, said annular contact being provided with projections for engagement with said spring contacts whereby rotation of said binding terminal carrying member will cause said spring contacts to move to a position in which they can be easily disengaged from said annular contact.

23. An attachment plug cap formed of insulating material and provided with spaced apart recesses, contact members provided with base plates embedded within said insulating material and each having a portion pro ecting" into one of said recesses,-

and binding screws located in said recesses and engaging the projecting portion of the respective base lates.

24. In a devlce of the class described a cap'formed of insulating material and provided with a recess, a contact member provided with a base plate embedded within said insulating material and having a portion projecting into said recess, and a binding screw located in .said recess and engaging the projecting portion of the base plate. 25. A separable attachment plug comprising a shell having a'threaded cont-act portion for engagement with a receptacle, said shell also having a contact portion integral therewith below said threaded'portion, and

a binding terminal carrying memberhaving a contact detachably engaging said integral contact portion,

In witness whereof, I have hereunto subscribed my name in the presence of two witnesses.

" REUBEN B: BENJAMIN.

Witnesses:

MABnn REYNOLDS, 'Cnamns G. Core. 

